Bug Description

Update: 6/12/2012
This bug is about a complete system lock-up. No other TTYs can be started. Mouse doesn't move. Keyboard doesn't react. The only solution is hard reset.

Seems to happen on a variety of configurations, including nVidia, ATI and Intel graphics.

If you are still able to TTY or SSH into other sessions, move the mouse or use the keyboard, file another bug.

Thx. Joris V. (brains).

Update: 5/21/2012
Updating the kernel to 3.3.6 as suggested by Michael in #91, the system seems stable, no freezes yet in 5-6 hrs of using and watching videos for couple of hrs.

Original description:
I recently installed newly released ubuntu 12.04 LTS 64 bit version on my desktop. And it is frequently freezing, for the first few hours it ran smoothly and when I started watching videos it started freezing randomly.
I have to use hard restart every time.
Initially it was only during videos but now even during normal browsing it is freezing.

I am using on board graphics and do not have any graphics card installed.

Can someone please help me here, I really love the new looks of 12.04 and it bugs me not being able to use :(

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

I have tried to not log in to X with lightdm, but instead just do a alt+f1 and go straight to console and I get a total freeze even.

Tried to connect from the outsite but the ip of the machine in question was not responding. So it is a total freeze.

After installing, some reboots, installing propietary nvidia driver 295.40, which worked fine for me and working with the desktop for a while I got my first freeze, since then, I have tried uninstalling the nvidia propietary driver but I still get freezes, quicker freezes even.

This also affects me. It seems to have a higher chance while browsing the web, regardless of the browser I use.
When it freezes, nothing but the cursor responds. I am using drivers from xorg-xserver-video-ati, no proprietary driver.

Hi, I'm also experiencing random freezes. Same symptoms: nothing but the cursor responds.
I have and AMD Radeon HD 6600M Series.
I DID NOT installed the suggested fglrx driver during the installation.
My machine is a Dell Vostro 3550.

I also have these random freezes (Pangolin 64 bit on a Acer 5720 laptop with Nvidia Graphics and the restricted / Closed source Nvidia driver installed).

I have noticed though that it is 'only' the screenoutput that freezes/ comes to a halt. Yes, the mouse cursor still moves, but nothing else seems to happen. But as I was copying lots of files and my screen freezed I did not touch my system until I was confident that the copy process should be ready: in fact the control leds of my HD worked! and my Wifi indicator also worked (I was also downloading a file).

After a while (led of HD and Wifi returned to idle) I switched off my system and rebooted the system. The files were copied correctly and my download was saved properly in my downloads directory.

I have also noticed that starting any browser (Firefox / Chrome) will hang the system more quickly. I have also noticed that other 'screen-intensive' software like e.g. shotwell or any fotoviewer will cause the system to hang if used heavily.

This bug seems to be highly related to screen output and apparantly nothing else. As Pdparo reports this on AMD Radeon as well (and even without the closed source driver installed) it is most likely not a problem directly caused by those drivers.

I have noticed that my screens sometimes 'flashes' (on/off, but then very very fast) as it seems to refresh the screen.

If you google this subject you will find lots of posts in forums as well: this seems to be a huge issue!

I use a freshly installed Ubuntu 12.04, and when I log under unity (3d) the GUI freezes after some time randomly. It can be when I surf the web with firefox or when I read a pdf file in evince. The mouse still moves on the screen, but nothing happens when I click somewhere. The system goes on working, for example, the music in rythmbox does not hang.

I think the problem is due to compiz, as no problem occurs when I log under unity2d.

I'm also having a similar complete freeze, no mouse movement. Fresh install 12.04 32bit is freezing every so often. Was watching a video earlier, noticed the curser was no longer moving for me then the video started shuddering. Was typing an email a few minutes ago when it froze again. I think this has happened like 5 or 6 times now. I have to hold the power button to shut it down, then when it starts again it stops at the colored screen but has a black section across it with colored lines around the edges of the black, press the reset button and it will boot to the grub boot menu. From there it starts ok but long boot time.

Same problem here, freezes about once every work day, which is rather alarming. Mouse moves and music keeps playing. I can Ctrl+Alt+F1 into the console, but if i try to go back without restarting anything, it will lock down completely, with a hard reset left as the only option.

Problem : Ubuntu 12.04 freezes , not able to click any button on keyboard or mouse , unable to go to console or reboot. the screen looks 3/4th black and 1/4th grey color. power off is the only option.

some more details.
I am using Intel i5 Dell laptop with 8GB RAM, Upgraded from Ubuntu 11.10 to 12.04, while this happend , I was using virtual box VM, JDeveloper and Mozilla Browser was Open . I often used to get "crash report" with send message button .

Conclusion : Ubuntu 11.10 seemed to be very stable - for 2 years it never crashed. But with 12.04 - its been hard to work

It looks like we may have two separate bugs. People who have their xsession mostly freeze but can still access the console and move the mouse, and those whose systems completely lock up. I'm getting the 'completely locked up' problem.

I started with the default nvidia drivers. I would get almost daily system freezes so I upgraded to the latest ones available from the 'Additional Drivers' menu. I still had daily system freezes, so I disabled the nvidia drivers from the 'Additional Drivers' menu and started using the nouveau drivers. This still locks up daily. It doesn't matter if I'm using the system or not, sometimes I'll find it frozen when I get up in the morning.

I'm using 12.04 64 bit with kernel 3.2.0-24-generic #37-Ubuntu SMP. This computer was rock solid before my upgrade to 12.04. I can see errors in the /var/log/syslog file at the time of the system freeze. I get messages like the one below. Sometimes I'll get many register dumps, one for each CPU in my 8 core system. The process name is always different as well, but it's always a BUG: soft lockup error. For those experiencing just the X freezes, but can still log in remotely or on the console, it would be good to know if you see something similar. It might help determine whether these are two separate bugs or the same bug that affects people differently.

I can freeze my 64 bit 12.04 desktop by opening a few windows (firefox, thunderbird, rhythmbox) and holding down alt-tab for a few seconds. My home server is freezing about every 24-48 hours and my software RAID isn't very happy about being constantly rebooted.

In some instances the mouse pointer can move, other times it is frozen. Music continues to play but starts getting patchy. The times where I have had top open, system load skyrockets.

I'd love to help diagnose this, but am uncertain what info I can give when things freeze up. I can reproduce this freeze on demand. What diagnosic info can I give?

The freezing is so bad I'm often unable to switch to a terminal with Ctrl-Alt-F1, and when I can't I can't get past the password prompt. The whole thing just seizes up. I could try having a terminal open from another machine and watch the behaviour of top.

Switching to nvidia drivers 295.49 and fixing a conflict in CompizConfig where both the Unity Application switcher and Application Switcher were activated simultaneously seems to have resolved the issue on my work computer. Crossing fingers that I can fix things when I get home...

I'm adding an update to my previous post, system has froze 5 times this morning and I have part of a log file from the incidents. Every freeze shows the same entries and can not access terminal through ctrl+alt+f2... -----------------

I've used ctrl-alt-fn+F1 to switch to another terminal and open a sudo bash shell and then back to my 64 bit 12.04 LTS Ubuntu Desktop (Lenovo Thinkpad E520) to keep working as long as possible before having to do a hard reboot.

Freezes happen less frequently when (a) logged in with the Ubuntu 2D option and (b) fewer applications are running.

When the freeze happens, I can't generally toggle back to the open bash shell on F1 because the keyboard and cursor are not responsive.

However, a few times, the system has become sluggish before freezing, and I was able to toggle back to the shell and use "top" to look for obvious malefactors.

So far I have not observed any large spikes in cpu use or memory or other strange numbers before the freeze made the entire system unresponsive. (I should note that I'm inexperienced at investigating this type of problem.)

Without help, I don't know how to ssh into the system to observe the freeze in real time and, because I'm supposed to be working at my regular job, I lack the minutes needed to work out how to do it. If I can get some time this weekend, I will call someone to help me and try it out.

Would it be helpful to post the output from dmesg and /var/log/syslog even if collected *after* a hard reboot? If there is other information that would be helpful, I can try to gather it.

Not sure if its related but i have a similar problem after the upgrade from 10.04 to 12.04.
I usually get a freeze when i close tabs in my browser (often with flash elements, Opera) or just opening a link with a flash video.

After a while opera will be responsive again since the plugin are called in a separate process (plugin-wrapper) which crashes and will start again.

I've been using the last kernel released with 11.10 since my crash yesterday. So far, I haven't had any problems. If I can last another day, I'll be 95% sure that solved the problem. I don't think I've gone 2 days since my upgrade on this computer. Oddly enough, I've upgraded 3 other laptops as well, one of which has an nvidia Quadro NVS 140M, but so far only my dual xeon w/ 24G ram & nvidia gt9600 workstation is having this problem. Only one of my laptops is running x64, but the one with the nvidia card is i386.

It looks like some people suffering from this problem have ATI cards and/or are on i386 as well, so maybe that isn't the common denominator.

I've trying to do some lite work today fixing my conkys that got messed up from stupidly installing 12.04 and had a freeze every 5-8 minutes for 2 hours, it won't be long and I'll have to replace my reset button o.O I should have stayed with 11.04.
Was using gedit and viewing my home folder only so it's not like my i3 or Nvidia card were working so I doubt it has anything to do with system usage.
Confirmed......but no importance ? There's gotta be thousands of systems that are doing this and it's not labelled critical or assigned ?

After a large update yesterday including Compiz I hoped we would have some solution. Nope. My system still randomly freezes and my screen flashes like a strobe light in the discotheque sometimes.

What really bothers me is that if you google you see that lots and lots of Pangolin users suffer from this bug (over 200.000 hits) yet this bug hasn't been assigned yet. Solution to be far far away this probably means, or we must hope that some update will bring the solution accidentily.

If this is the way Ubuntu works these days, I'd rather spent a hundred bucks and get that so called crappy Windows 7: it at least doesn't freeze a twenty or thirty time a day. Or I will move away to another Linux distro that takes it's users a bit more serious.

For now to have a working system I will probably downgrade to 11.10.

I think it's mainly due to the fact that Ubuntu has been moving away from mainstream development with Unity and multiple monitor support. Don't get me wrong: I like the Unity concept and I also hope for a good multiple monitor solution for Linux, but I'd rather see efforts bundled instead of forked.

For now: please please please developers dive into this nasty bug. We (the users) are suffering: we need a GUI that works!

I tried compiling the kernel from kernel.org, version 3.3.5, it took a while but it also freezed completely (machine completely unresponsive, no mouse or ping or ctrl+alt+f1 out of it) same as with ubuntu stock kernel.

I am including my syslog of the whole evening with the two different kernels (ubuntu, kernel.org 3.3.5, but since the freeze is sudden never gets anything substantial logged).

I have the same problem with the 32 Bit version.
Frequent random lockups, the only thing that will work is the mouse cursor, hard reset to recover.
The problem has also occurred during normal shutdown and system hangs and needs to be powered off to shutdown.
Have been forced to go back to Windows!
11.10 was working perfectly.

@ Norm. That's bad. I wanted to try the 32 bit version as I encounter the freezes with the 64 bit version. But if the 32 bit version does the same than that's no way out. Did you try the 64 bit version as well? It's necessary for the solution of this bug to know if both versions (64 and 32 bit) have this bug.

I will probably try the 32 bit version as live version and test if it does have the same lock ups. If not I will install it and test it further. I would still love to use Ubuntu 12.04 and I don't mind to use the 32 bit version as the 64 bit doesn't really have any direct advantages for me.

Strange that the importance of the bug is still undecided and has not yet been assigned to anyone. 25 users that take the trouble to report this bug must imply that there are at least hundreds, if not thousands of users running into trouble with this bug. And this bug is a real show stopper as it completely freezes the system! I ask my self what the developers are doing? Are they asleep?

What we really need is to stop adding to this bug report. If you still have a bug, it is a different bug from this bug. If you are still experiencing freezes, file a bug report apart from this one, and include the files they ask for (I was new and didn't do this at first but there is a helpful reminder generated by a bot on how to use apport to collect this info and update your bug report very easily via the command line).

OK, i know, this bug should be stopped posting to but i could kind of workaround it:

A PC i am responsible for was crashing with 12.04 and 12.10 every hour nearly. What solved it for me:

1) Updated to raring ringtail (upcoming 13.04), kernel 3.8.x. (Why is raring THAT stable right now? It works really well here! But pls keep in mind its pre-beta. Though with this crashes here, you should be good to go for an upgrade ;-) )
2) Updated firmware on the harddrive (a SSD in my case)
3) flashed new bios (ASROCK mini itx mainboard h61m-itx)

I'm still having this issue (2012-12-21 comment 609). Very annoying! Freezes seem to be completely random, at the best my laptop has been running fine longer than month, but for example during the past two weeks, maybe ten freezes.

Yes, mouse not moving, keyboard not responding, no ssh, Ctrl+Alt+F1 not working, no tty.. Closing lid does not suspend. The only option is to power off the computer from the power button and start over.

The same laptop also has W7 and RHEL6 installed, they run without problems..

Ubuntu 12.04.2 LTS with the latest updates. Please, see the lspci-info attached for the details. No proprietary drivers, Intel Ivy Bridge.

in #46. I just went back to 10.04, the instability of 12.04 is just ridiculous. I hope that a kernel developer is following this discussion and might find a hint in the syslog extracts I posted under the other number.

If you have this bug, you are in luck, just updating your kernel to 3.4 will fix it. If that doesn't work, then you do not have this bug. You have something else. See if your symptoms or situation match this bug:

I want to confirm the bug for LMDE (Linux Mint Debian Edition) running a 3.2.0-4-amd64 kernel.
- Also complete freeze, even no tty; at least once a day, sometimes 4 times a day.
- Workaround: do not start Firefox with a video in a tab waiting to be viewed in a spare moment
- Solution: kernel upgrade. To 3.8.8 in my case.

Few weeks ago we moved from 10.04 to 12.04 at work. Mostly because of newer machines had problems with older kernels (no SATA, no sound). I have to admit that 10.04 was light years away from 12.04 when it comes to stability. There was mean time between crashes measured in weeks, when 12.04 can have 10 crashes in one hour. It's really disappointing. Right now I'm upgrading kernel to 3.2.0-41 and hoping it will fix freezes and crashes before coleagues at work crucifies me.

Will report after few days if that helped. If not, I have no clue what will I do since I'm running out of options. So if anyone can help me pointing in right direction or what can I do to help developers find and kill this annoying bug, I'm here.

Oh and those 60 machines at work are all from DELL, models Optiplex 380SFF, 390 SFF and 1030SFF. Just what's built in, with Intel graphics and all runing on Gnome Classic - no Unity. All machines are connected to network and has mounted Samba and NFS shares, each one of 100 users uses mostly Firefox, Thunderbird, LibreOffice, Audacity, VLC and some custom developed software.

Ironicaly Ubuntu HCL lists those machines as compatible when clearly they far from that.

So after 3 months I'm back here to check what's up with this bug. I have been using Windows in the meantime.
Seems like not much going on here. No solution yet?

Ok someone suggessted kernel 3.8.8 which I haven't tried. But since I've tried all kernel 3.2.x up to 3.6.x, I'm a bit reluctant to try 3.8.8. Can someone else confirm this kernel version fixes this bug?

I think this bug is not solved on 12.04 LTS. If it's a kernel bug, the patch should be backported to the latest official 12.04 kernel and delivered via normal software update.

Some people suggested for example to update to kernel v. 3.3.6 available here: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3.6-precise . That kernel is more than one year old and does not contain many important security fixes. If start using something like this, maybe should update to the latest kernel from kernel.org and compile it. I think most of the users don't want to do that.

I run many computers with 12.04 without problems, but I have fatal and occasional freezes only with my newest Intel Ivy Birdge laptop. (see #774)

I am not sure, but i had a freeze another day on Windows XP that was very similar to these on Lubuntu and Ubuntu, but happened only one time contrary to Lubuntu and Ubuntu that happens all the time i am using Blender or watching a video.

I also had the problem where my kubuntu 12.04 install was completely hardware freezing - i.e absolutely no response from any input device and in particular CTRL+ALT+SysRq REISUB was not responding at all either.

I found the problem was happening close to when I was switching the external monitor on & off (I switch it via a KVM switch).

Note that I use x11vnc to remotely connect to the same desktop, and I think that may have helped trigger the fault.

I updated ALL installed software, but to no avail, it was happening 3 or 4 times a day ...

*** THE FOLLOWING FIX WORKED FOR ME -been ROCK SOLID for a week now ***

476 users and still no attention from the developers. 8 MONTHS after the release of Ubuntu 12.04 and still having whole system freezes on a daily basis. In two fully different computers, with the i386 and amd64 versions of Ubuntu 12.04.

Users that turn their computers off after a several hours session will almost never notice the freezes. It is us users who want to leave our computers running for more than one day, who are suffering this problem. The average running time before a whole system freeze is about 10 hours, though sometimes it may happen in much shorter/longer time. Please somebody explain me that, or I will start elaborating conspirational theories, because it really FEELS as there is a hidden timer in the kernel, with an random average pre-set running time around ten hours.

Is this part of some fight against P2P piracy? My teenage eMule times are far beyond, and I don't much know about how the corresponding programs work today, but I badly need to run numerical simulations at home, and some of them take about 3 days. Most times they are ruined by these freezes. I already have changed the distro to an older Fedora in one of the computers, so that my simulations run fine there. But my laptop still has (K)ubuntu 12.04. I am still waiting, hoping and apt-get updating, for months now. But I am getting tired. I may give up soon and say goodbye to a long, personal tradition of confidence on Ubuntu. I am getting sick of waking up in the morning, going to the computer and seeing that it has frozen again during the night.

I also switch to Debian 7. But I had still freezes.
Now that I am running kernel version 3.12.0 it seems that my system becomes stable. I saw 'only' one freeze in 14 days.
After all (I am affected from this problem still 10 month!) I guess that the problem is issued by the wifi. But I did not know how to test or verify this.

I can confirm that it's caused by compiz not unity.
I have removed unity and activated the compiz application switcher as alt+tab on precise doesn't work.
Often, when I press alt-tab to switch application, ubuntu freezes and I cannot even use ctrl+alt+f1
It even happened with alt-f4 to close a window.
Now I understand why alt+tab has been disabled on precise.

using the series 3.2.0-xx of kernel on my Ubuntu 12.04.03 the system just get stuck at ubuntu's dots screen every 4 or 5 boot, nothing works, not even keyboard just it is posible turn off by a hard reset.

After upgrade the kernel to 3.5.0-37-generic #58~precise1-Ubuntu SMP Wed Jul 10 17:48:11 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux,
all things was going better...
from this upgrade, system run well and don't stuck at boot or hangs.

I have been facing this problem for a long time now and it still doesn't seem to get fixed. To me it happens most often on multimonitor using HDMI, but also with a single monitor or multimonitor using VGA.

I have also been facing this problem for a long time. It began with 12.04LTS as I remember. Previously the system was stable as a rock running 10.04 LTS.

Tried to re-install the OS from scratch, but still facing the problem. Changed Video card, main board. Swapping RAM tried different graphics drivers, different available kernels but there is still random freezing. Could not effort to change the $1000 CPU...

To me it happens most often when kicking on a link in Thunderbird to be opened in Firefox. Complete freeze, but the mice some times still moves around. No response from keyboard at all (numloc and capsloc LEDs does not change). Some times the system freeze when running in idle, and I discover this at logon screen. Normal uptime is about two three days between forced HW reboots.

The strange about this bug is, that my kids runs a PC Intel Core i7-3770 3,4GHz Asrock/Gigabyte B75-Chipset mATX without facing any problem at all. I'm also user on the PC, running Gnome classic and compiz. I never log out, just switch user. It only reboots when applying new packages that requires a reboot, els its always running stable.

I am also facing the same issue.
But since I am running kernel version 3.12.x the system is very stable. Freezes only once in a week with 3.12.5 (before I had freezes 1-3 times a day)
I am not sure if it is the kernel version. As I am now working with Debian Jessie I also got a lot of updates from firmware to wifi driver. I am still thinking about if the issue could be related to the wlan area/power management....?

I was originally running openSuSE 13.3 w/KDE, but as this system is meant to be a multimedia system, it was causing more trouble that I wanted to deal with. I do not recall it freezing at any time.
I then installed Kubuntu 13.10 64bit as the multimedia support is better than SuSE. This is when I started to get multiple lock ups. I thought maybe it was due to something not being happy with 13.10, so I installed 12.04.3 LTS w/ KDE 4.12. I also removed the 8GB 'Team' memory and installed a single 4GB ADATA 1333MHz DIMM.
This appeared to have resolved the issue, but it locked up on me three times yesterday. Once while using Amarok (remote mySQL database & collection on a FreeNAS NFS share), once while just using the desktop and another while attempting to play an 800MB .MKV file in XBMC standalone (remote mySQL, file located on a FreeNAS NFS share).
I've checked the various logs, and there does not appear to be anything of any relevance as nothing 'crashes' exactly, the entire system just locks.

During freezes trackpad doesn't work. Some have upgraded kernel from 3.2 to 3.4 and have solved their issues. I am running kernel 3.8 and still facing issues. The Xorg display drivers seemed to create problems so running Additional Drivers for nVidia recommended by Ubuntu. Any views on how to proceed further? Strangest thing is never once a bug report was generated after hard reset of the laptop. Any help is appreciated. Thanks!

I was running different Nvidia graphic cards with different proprietary
Nvidia drivers (see my previous post).

Changed the Nvidia graphic card to an old HD 5670 Radeon AMD and loaded
the catalyst drivers. *Until now no more system hangups has appeared.*
Will try e newer AMD R9 290 card later on.

This explains why my kids PC did not hang at all, due to running it on the
internal Intel CPU graphic.

So for my system, it seems that the freezes was related to graphic card. I
don't know if the bug is in the proprietary Nvidia drivers or in Ubuntu.
Sad to change from the Nvidia, because it always worked like a dream in
Linux.

Den 27 jan 2014 12:11 skrev "VaidhyM" <email address hidden>:

> I am running Ubuntu 12.04 LTS. I am facing the full freeze issues too.
> So much that its froze for 12 times in 2 hours. Hard Reboot is the only
> way to revive the system. The configuration is,
>
> Intel Core i7 2630QM @ 2.00 GHz
> 4 GB RAM (2x2) + 2 GB Swap
> nVidia GT 540M
>
> During freezes trackpad doesn't work. Some have upgraded kernel from 3.2
> to 3.4 and have solved their issues. I am running kernel 3.8 and still
> facing issues. The Xorg display drivers seemed to create problems so
> running Additional Drivers for nVidia recommended by Ubuntu. Any views
> on how to proceed further? Strangest thing is never once a bug report
> was generated after hard reset of the laptop. Any help is appreciated.
> Thanks!
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/993187
>
> Title:
> ubuntu 12.04 completely freezes frequently.
>
> Status in “linux” package in Ubuntu:
> Fix Released
> Status in “xserver-xorg-video-intel” package in Ubuntu:
> Fix Released
> Status in “linux” source package in Precise:
> Fix Released
> Status in “xserver-xorg-video-intel” source package in Precise:
> Fix Released
>
> Bug description:
> Update: 6/12/2012
> This bug is about a complete system lock-up. No other TTYs can be
> started. Mouse doesn't move. Keyboard doesn't react. The only solution is
> hard reset.
>
> Seems to happen on a variety of configurations, including nVidia, ATI
> and Intel graphics.
>
> If you are still able to TTY or SSH into other sessions, move the
> mouse or use the keyboard, file another bug.
>
> Thx. Joris V. (brains).
>
> Update: 5/21/2012
> Updating the kernel to 3.3.6 as suggested by Michael in #91, the system
> seems stable, no freezes yet in 5-6 hrs of using and watching videos for
> couple of hrs.
>
> Original description:
> I recently installed newly released ubuntu 12.04 LTS 64 bit version on
> my desktop. And it is frequently freezing, for the first few hours it ran
> smoothly and when I started watching videos it started freezing randomly.
> I have to use hard restart every time.
> Initially it was only during videos but now even during normal browsing
> it is freezing.
>
> I am using on board graphics and do not have any graphics card
> installed.
>
> Can someone please help me here, I really love the new looks of 12.04
> and it bugs me not being able to use :(
>
> Below is my hardware configuration:
> Proce...

Since then, although it has been pretty stable under 3.4.0-030400.201205210521, I was still getting [albeit less frequently] complete freezups that show exactly the same symptoms as I reported before.

The following NEW FIX has in contrast been COMPLETELY ROCK SOLID [not a single crash yet] in so far as no hardware freezeups are concerned, and I have been hammering the video display on the main KDE login session. I am also remotely accessing that session through x11vnc, and also run 2 separate NX sessions in the background, all of which are very busy & used interactively. When I used to try running 2 busy NX sessions + an x11vnc session on the main KDE login session, it would not take too long for a complete hardware lockup to occur - within an hour easily with 2 busy NX sessions [I only had good stability with the one x11vnc session to the main KDE desktop under 12.04.x LTS]. I am also running virtualbox guests in the NX and x11vnc sessions [Note that I have 32GB memory so it's viable to run lots of sessions & virtualbox guests].

The FIX is quite simply: upgrade from Kubuntu 12.04.5 LTS -> 14.04.1 LTS (note that as of right now, if you upgrade to 14.04, you will in fact be taken to 14.04.1.

Hey here we are in bug land and i am reporting the same olde same ole lock up on my 14.04 install. it bugs me. out there in internet land on my eeepc netbook 1g ram 320g hd and quickly all goes stop. no keyboard or mouse => hard reboot and on we go, over and over. install lubuntu to no availment of improved netland, just keeps on going lock. any clues greatly appreciated